Working apparatus and working method for circuit board

Abstract

In estimating a curved surface model by approximating the shape of the board surface of a circuit board, auxiliary measurement spots are set other than measurement spots on the board surface, eligibility as a sampling displacement magnitude in estimating a curved surface model is determined according to a difference in a displacement magnitude from a work reference surface. When the sampling displacement magnitude is determined to be ineligible, a new measurement spot is reset. By this operation, a local increase and decrease in the displacement magnitude due to a discontinuity of the board surface exerts no influence on the estimation of the curved surface model, and the curved surface model approximated more closely to the shape of the actual board surface is estimated, leading to an improvement in the work quality with the working height adjusted to the proper height.

1. A working apparatus for a circuit board, the working apparatus comprising:
 a measuring means for measuring measurement displacement magnitudes of the circuit board from a work reference surface at each of at least three measurement spots set on a working surface of the circuit board and at least one corresponding auxiliary measurement spot set in a vicinity of at least one of the at least three measurement spots, respectively; 
 an operation means for determining whether a difference between a maximum value and a minimum value of the measurement displacement magnitudes from the work reference surface measured by the measuring means at each of the at least three measurement spots and the at least one corresponding auxiliary measurement spot is not greater than a threshold value, estimating a shape of the working surface of the circuit board by a curved surface model based on the measurement displacement magnitudes of the at least three measurement spots that have been determined to have a difference between a maximum value of the measurement displacement magnitude and a minimum value of the measurement displacement magnitude not greater than the threshold value, and calculating operation displacement magnitudes of the curved surface model at curved surface model measurement spots on the curved surface model which correspond to the at least three measurement spots, on the work reference surface, used to estimate the curved surface model; and 
 a correcting means for correcting a working height in performing works on the working surface of the circuit board on the basis of the operation displacement magnitudes of the curved surface model calculated by the operation means. 
 
     
     
       2. The working apparatus for a circuit board as defined in  claim 1 , further comprising:
 an adaptability determining means for comparing the operation displacement magnitudes at each of the curved surface model measurement spots with the measurement displacement magnitudes at each of the at least three measurement spots used to estimate the curved surface model to determine whether a difference between each of the operation displacement magnitudes and each of the measurement displacement magnitudes, respectively, is not greater than a threshold value and determining that the curved surface model is adapted upon determining that the difference is not greater than the threshold value. 
 
     
     
       3. The working apparatus for a circuit board as defined in  claim 1 , wherein
 the operation means estimates a shape, for each of a plurality of compartment working surfaces obtained by compartmentalizing the working surface of the circuit board into a plurality of regions, the shape being based on the measurement displacement magnitude. 
 
     
     
       4. A working method for a circuit board, the method comprising:
 setting at least three measurement spots on a working surface of the circuit board; 
 measuring measurement displacement magnitudes from a work reference surface of the circuit board at the at least three measurement spots; 
 determining whether a measurement displacement magnitude at each of the at least three measurement spots is eligible as a sampling displacement magnitude; 
 setting, upon a determination of ineligibility, a new measurement spot in place of one of the at least three measurement spots that has been determined to be ineligible and measuring the measurement displacement magnitude at the new measurement spot to determine eligibility of the measurement displacement magnitude at the new measurement spot, or estimating, upon a determination of eligibility, a shape of the working surface of the circuit board by a curved surface model based on the measurement displacement magnitude at each of the at least three measurement spots and calculating operation displacement magnitudes of the curved surface model at curved surface model measurement spots on the curved surface model which correspond to the at least three measurement spots, on the work reference surface, used to estimate the curved surface model; and 
 performing works on the circuit board by correcting a working height in performing works on the working surface of the circuit board on the basis of the operation displacement magnitudes of the curved surface model. 
 
     
     
       5. The working method for a circuit board as defined in  claim 4 , wherein
 at least one corresponding auxiliary measurement spot is set in a vicinity of at least one of the at least three measurement spots, respectively, in setting the at least three measurement spots, 
 the measurement displacement magnitude of each auxiliary measurement spot is measured in measuring the measurement displacement magnitudes, and 
 it is determined that the measurement displacement magnitude is eligible in determining an eligibility of the measurement displacement magnitude, when a difference between a maximum value and a minimum value of the measurement displacement magnitudes at each of the at least three measurement spots and the at least one auxiliary measurement spot set in the vicinity of at least one of the at least three measurement spots, respectively, is not greater than a threshold value. 
 
     
     
       6. The working method for a circuit board as defined in  claim 4 , wherein
 it is determined, after the curved surface model is estimated, whether the curved surface model is adapted to the working surface of the circuit board, and 
 when the curved surface model is determined to be not adapted, a new curved surface model is estimated by additionally setting a new measurement spot, in setting the at least three measurement spots. 
 
     
     
       7. The working method for a circuit board as defined in  claim 6 , wherein
 in determining an adaptability of the estimated curved surface model to the working surface of the circuit board, the operation displacement magnitude at each of the curved surface model measurement spots is compared with the measurement displacement magnitude at each of the at least three measurement spots, and it is determined that the curved surface model is adapted when a difference between each of the operation displacement magnitudes and the measurement displacement magnitudes, respectively, is not greater than a threshold value. 
 
     
     
       8. The working method for a circuit board as defined in  claim 4 , wherein
 in estimating the curved surface model, a shape of a compartment working surface is estimated by the curved surface model based on the measurement displacement magnitude for each compartment working surface obtained by compartmentalizing the working surface of the circuit board into a plurality of regions.